WorksheetsElectrical Engineering Quiz
Total questions: 51
Worksheet time: 26mins
A transformer has an input power of 20kW and power losses of 920W, the overall efficiency is
a) 9.4%
b) 94.5%
c) 95.4%
d) 9.5%
What is this component?
a) A transistor
b) A triac
c) A diac
A thyristor
An arrow appearing through an electronic symbol means the device is:
a) Preset
b) Light emitting
c) Variable
d) Fixed
A conductor is placed in a static magnetic field and a current is passed through it. The force exerted on it can be calculated by
a) F = BLV
b) F = BIL
c) F = ma
d) F = mg
M_ is the abbreviation used for:
a) Microhms
b) Milli-Ohms
c) Megohms
d) Meggerohms
A length of copper wire has resistance 8 Ω. What would be the resistance if the length was halved and the cross sectional area doubled:
(a)
A 9V battery is connected across a set of resistors in series, values being: 3 Ω, 12 Ω, 160Ω and 68 Ω. The current flowing in the circuit is:
a) 233A
b) 2097A
c) 25.89A
d) 37mA
A power supply has four diodes connected in ‘bridge’ after the transformer. Is this called a:
Half wave rectifier
Full wave rectifier
Full wave smoother
Half wave smoother
What is this rule and where is it used?
Left hand rule, motors
Right hand rule, generators
Left hand rule, generators
Right hand rule, motors
What is the SI unit for magnetic flux?
Tesla
Coulomb
Angstrom
Weber
What is the function of a dielectric within a capacitor
Holds electric charge
Connects the electric charge to outside circuits in two places
Acts as an insulator between the charged plates
Allows the flow of electrons in pairs
Identify this electronic component
Diode
Transistor
Thyristor
Resistor
The direction of a magnetic field surrounding a current-carrying conductor can be found using which rule?
Fleming’s right hand rule
Fleming’s left hand rule
Maxwell’s corkscrew rule
Lenz’s Law
The insulation resistance of two circuits is 40MΩ and 36MΩ respectively. When tested together what is the total insulation resistance:
60MΩ
0.125MΩ
22MΩ
18.94MΩ
What symbol is this:
Diode
Zener Diode
Photodiode
Photocell
A 230V AC supply has an RMS voltage of:
163V
325V
400V
230V
An electronic device that alters its value to different levels of light is:
A photo transistor
An opto coupler
A fibre optic link
A capacitor
The peak-to-peak voltage of a sinusoidal waveform is:
1/2 x peak value
The peak value
2 x peak value
4 x peak value
An electronic component has the following connections: Base, Collector and Emitter. The component is:
A transistor
A triac
A diac
A thyristor
The following resistors are connected in series to a 230V supply: 12Ω, 24Ω, 48Ω. Calculate the current taken by the 48Ω resistor.
84A
0.36A
2.74A
48A
A conductor of length 1m is placed in a static magnetic field of strength 10mT and a current of 2A is passed through it. Calculate the force exerted on it
20N
2N
0.2N
0.02N
Which of the following is the RMS value for an a.c. voltage having a peak value of 325V:
415V
460V
230V
400V
A steady current of 2.5 A flows for 90 seconds into a capacitor, calculate how much charge has been accumulated on the plates of the capacitor:
0.0278C
3.75
225C
92.5C
Three resistors of value 10Ω, 12Ω and 48Ω are connected in parallel with a voltage supply of 24V DC. Calculate the volt drop across the 10Ω resistor:
0.167V
4V
12V
24V
What is Fleming's right hand rule mainly used for:
Generators
Force on a current carrying conductor in a static magnetic field
Motors
Transformers
A circuit consists of three resistors in series, of values 18Ω, 26Ω and 42Ω, connected in series to a 24V supply, determine the power dissipated by the whole circuit:
6.7W
86W
0.28W
4864W
Which of the following devices work as a result of mutual induction:
Solenoid
Transformer
Relay
Contactor
What kind of capacitor is this:
Paper
Electrolytic
Mica
Tantalum bead
Which of the following devices could be used to efficiently detect light and thus be used in a circuit to switch on a light at night-time:
Opto-coupler
Fibre-optic link
Photodiode
LED
What kind of circuit will provide this output wave from an AC supply:
Full-wave rectifier
Rectifier with smoothing
Half-wave rectifier with smoothing
Half-wave rectifier
A Coulomb is:
Rate of flow of electrons
Rate of flow of protons
Quantity of charge
All the above
Calculate the resistance of 125m of 1.5mm² Aluminium wire given the resistivity of Aluminium is 28.5 x 10⁻⁹ Ω/m:
3.42Ω
5.34pΩ
2.375Ω
6578.94Ω
A dc current of 0.6A flows for 300ms into a capacitor, what is the charge:
2C
0.36C
0.18C
4C
For the lines of magnetic flux shown here to exist between two magnets, what must the magnetic poles be at A and B, respectively:
South North
South South
North North
North South
What is this rule simply used for in magnetism:
Finding the direction of the traffic on a busy road.
Finding the direction of the Magnetic Field in a conductor.
Finding the direction of Force, Field and Current in generators.
Finding the direction of Motion, Field and Current in motors.
Calculate the Flux density of a bar magnet whose magnetic flux is 781.25μWb with a square section of material of 25mm x 25mm.
32T
32mT
125T
1.25T
A conductor of length 3m is placed inside a static magnetic field of strength 5mT and a current of 0.5A is passed through it. Calculate the force exerted on it:
7.5mN/m
7.5N/m
30mN/m
0.83mN/m
The peak voltage of a sinusoidal waveform is 566V, what is the RMS voltage:
566V
400V
283V
200V
To operate in forward bias, a diode will conduct when a positive voltage is applied to the:
Anode
Cathode
Gate
Base
Three resistors, all of value 6Ω are connected in a series and parallel combination, giving an equivalent resistance of 9Ω. How are they connected:
All in series
All in parallel
Two in series, which are then connected in parallel with the third
Two in parallel, which are then connected in series with the third
What electronic component is represented by this circuit symbol:
Capacitor
Variable Capacitor
Electrolytic Capacitor
Battery
Which electronic component does this symbol represent:
Diode
Triac
Transistor
LDR
What is the peak-to-peak value for an AC voltage having an RMS value of 400V:
566V
283V
400V
1132V
What does this symbol represent:
Variable Resistor
Thermion
An American fuse
Thermistor
What is this component:
Choke
Axial electrolytic capacitor
Ceramic resistor
Ceramic inductor
A conductor of length 0.7m is placed in a static magnetic field of density 0.4mT and a current of 0.9A is passed though it. Calculate the force exerted on it:
2.52N
252mN
252μN
25.2N
A 400V AC supply has an RMS voltage of:
400V
566V
360V
230V
Which of these is NOT an effect of the flow of electric current in a conductor:
Radioactive
Thermal
Magnetic
Chemical
A steady current of 50mA flows for 6 minutes into a capacitor when 9V is applied, how much charge will accumulate on the plates of the capacitor:
18C
0.3C
162C
3600C
A transformer has an input power of 15kW and power losses of 640W, the overall efficiency is:
95.7%
100%
99.9%
4.3%
Which direction will this conductor move:
Left
Right
Up
Down
